New (old) Amp Day! Mesa Boogie Studio 22+

no doz

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just grabbed this 80s mesa boogie studio 22+ in manhattan today for a steal, with the caveat that sometimes the sound cuts in and out intermittently. could be as simple as a loose wire or bad joint / jack, could be something more devious; but well worth the gamble either way

it's got a JBL K120 speaker in it that was reconed at some point. i need to remove the chassis to see what tubes are installed, but i think i can see some big old sprague blue atom caps through the chassis vent which would be very cool. it also has an accutronics reverb tank inside that looks interesting, a lot smaller than the ones i'm usually used to seeing inside amps

very excited to get this whipped back into shape. do any of you know these amps? hoping to find out what's good, what's lacking, which components to keep vs which to upgrade, etc. i've never used one before but i have a '91 dual rectifier that's been a lifelong companion, so my hopes are high

IMG_5720.jpg
 

uriah1

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Had that one. Great amp. Took different speakers well. Loud and sits well in band mix. Like a lot of boogies you got to find your setting in
Tone controls. Enjoy
 

red57strat

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just grabbed this 80s mesa boogie studio 22+ in manhattan today for a steal, with the caveat that sometimes the sound cuts in and out intermittently. could be as simple as a loose wire or bad joint / jack, could be something more devious; but well worth the gamble either way

it's got a JBL K120 speaker in it that was reconed at some point. i need to remove the chassis to see what tubes are installed, but i think i can see some big old sprague blue atom caps through the chassis vent which would be very cool. it also has an accutronics reverb tank inside that looks interesting, a lot smaller than the ones i'm usually used to seeing inside amps

very excited to get this whipped back into shape. do any of you know these amps? hoping to find out what's good, what's lacking, which components to keep vs which to upgrade, etc. i've never used one before but i have a '91 dual rectifier that's been a lifelong companion, so my hopes are high

View attachment 991730
I like these amps a lot. They're light and portable and have an old school kind of Boogie sound.

These amps cutting in and out is very often caused by dirty or fatigued FX loop jacks. Clean them, or even just run a cord connecting them, and see if it helps.

Most of these need new electrolytics by now (unless they've already been replaced). Some of the B+ resistors can need replacing and upgrading.
It looks like yours also needs a couple of potentiometers. Those are easy to change on these amps.

I don't recall if it's the .22 or the .22+ that can have switching power supply issues. There's a schematic with recommended upgrades.

Other modifications I like are adding a Tone shift and bright switches. You can use push/pull pots or install mini toggle switches- they fit in the vents in the back of the amp w/o drilling.
Also, you can add a lead drive control.

Although the components are mounted on the underside of the PCB, the PCB has plated through holes and most repairs and modifications can be made from the top of the PCB by dropping parts out and replacing them on the top. In fact, some parts should run cooler up there.

Does this amp have a small reverb tank running up the side of the cab or a tiny one inside the chassis? It's not difficult to install a full size reverb tank, but it'll still never be as lush as the reverb in a Fender amp- that wasn't Mesa's goal with reverb.
 
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no doz

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I like these amps a lot. They're light and portable and have an old school kind of Boogie sound.

These amps cutting in and out is very often caused by dirty or fatigued FX loop jacks. Clean them, or even just run a cord connecting them, and see if it helps.

Most of these need new electrolytics by now (unless they've already been replaced). Some of the B+ resistors can need replacing and upgrading.
It looks like yours also needs a couple of potentiometers. Those are easy to change on these amps.

I don't recall if it's the .22 or the .22+ that can have switching power supply issues. There's a schematic with recommended upgrades.

Other modifications I like are adding a Tone shift and bright switches. You can use push/pull pots or install mini toggle switches- they fit in the vents in the back of the amp w/o drilling.
Also, you can add a lead drive control.

Although the components are mounted on the underside of the PCB, the PCB has plated through holes and most repairs and modifications can be made from the top of the PCB by dropping parts out and replacing them on the top. In fact, some parts should run cooler up there.

Does this amp have a small reverb tank running up the side of the cab or a tiny one inside the chassis? It's not difficult to install a full size reverb tank, but it'll still never be as lush as the reverb in a Fender amp- that wasn't Mesa's goal with reverb.

what a helpful post, thanks so much don! finally had a chance to sit with the amp for a while and it sounds really cool

- first time i plugged it in i got intermittent signal loss after five minutes or so, had a hunch it might be the FX switching jacks so i plugged a patch cable btwn the effects send + effects return. immediately solved the issue. gonna clean the jacks but keeping a patch cable back there is as easy as it gets

- i haven't removed the chassis yet but from what i can see of the caps, they look like the OG ones from some gutshots i've found online. i also see some carbon comp resistors in there, might swap em for metal film if i think it'll help quiet the amp down a bit. gonna hunt down a schematic and assess that stuff / figure out the proper value for the two replacement pots

- all those mods sound super useful! the amp sounds killer so far but maybe a tad bit dark even with the treble dimed and presence high. also found myself wishing i had a lead drive control while i was playing around with it. going to study up on all those while i'm formulating my gameplan moving forward

- the amp definitely gets HOT, wouldn't be surprised if things inside the chassis were getting a little crispy. i might install a fan similar to the ones i've seen in mesa mark IIs. will be mindful of the possibility of top-mounting to the PCB to help with heat exposure

- this amp has the small accutronics tank in the side of the cab. it sounds decent but might be worth replacing eventually, esp if i can fit a full size one in there

- been finding the amp slightly boxy sounding so far, really interested to run it direct into my DAW and remove the speaker, cab, and room from the equation, see if the origin of that low mid fog is the circuit itself or a combo of that other stuff

thanks again, i really appreciate all your suggestions!
 

corliss1

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but i think i can see some big old sprague blue atom caps through the chassis vent which would be very cool.
Mesa had their own brand of blue caps they put in *everything* in that era. Get it serviced, they do run hot so even things that may not need to be replaced could get the solder touched up a bit.
 

gridlock

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Congratulations, a good one. My first Boogie was a Studio 22 (non-plus). A great sounding amp that’s lead me to quite a few different Mesa’s over the years.
 

Neptical

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Congrats OP!

I had a Studio 22+ with GEQ 25 years ago. I used it for many shows and it sounded fantastic. I eventually moved on up to Boogie Mark III heads ( own two since then). Underrated.
 

no doz

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Mesa had their own brand of blue caps they put in *everything* in that era. Get it serviced, they do run hot so even things that may not need to be replaced could get the solder touched up a bit.

ahh good call! found some gutshots online, they're definitely the mesa branded caps. i've built / worked on a handful of amps now, i'm gonna do some testing against the schematic and replace anything out of spec myself. will probably reflow all the joints as well

if i have to swap some of those blue mesa caps out, do you have a replacement you prefer or would recommend?
 

no doz

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Had that one. Great amp. Took different speakers well. Loud and sits well in band mix. Like a lot of boogies you got to find your setting in
Tone controls. Enjoy

do you remember which speaker you preferred in yours? i'm gonna get to know the JBL first before i make any changes but i'll keep a few in mind for the future

@no doz - I always use F&T when possible. I've went through thousands of them with no issues.

amazing, thanks so much!
 

uriah1

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do you remember which speaker you preferred in yours? i'm gonna get to know the JBL first before i make any changes but i'll keep a few in mind for the future



amazing, thanks so much!
Mine came with the boogie v30 . I ended up with the g12h30 anniv since it had a little more. The Alnico coffee can ev was also fun. Heavy though
 

klasaine

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Great amp!
I've had one since 1992. I replaced the speaker once because I blew the original 'black shadow'. I put a Vintage 30 in it. This was years ago and I do not remember noticing a huge difference at the time. As it's a low wattage amp, I usually run it pretty hot. For me, this amp has always been super reliable. *They can be a little 'hissy'. The high gain, white noise thing.
 

Stubee

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They are very cool little amps. A friend was gonna sell one so let me try it out and when I’d about decided to buy it he changed his mind about selling it. He looked to sell it again later but I’d moved on to a Pro Jr and was digging that.

I recall it was a pretty versatile little beast that could really sizzle. Have fun!
 

no doz

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Great amp!
I've had one since 1992. I replaced the speaker once because I blew the original 'black shadow'. I put a Vintage 30 in it. This was years ago and I do not remember noticing a huge difference at the time. As it's a low wattage amp, I usually run it pretty hot. For me, this amp has always been super reliable. *They can be a little 'hissy'. The high gain, white noise thing.

i noticed some carbon comp resistors in the gutshots i found online, i'm gonna do some research and see if replacing them with metal film resistors might help tame a bit of the hiss without changing the sound too drastically. and i'm really liking the JBL so far, it's super pristine sounding which is pretty different than any of my other cabs. you gave me the idea to try running the amp through my orange 4x12 later to see how it sounds with the V30s, thanks!

They are very cool little amps. A friend was gonna sell one so let me try it out and when I’d about decided to buy it he changed his mind about selling it. He looked to sell it again later but I’d moved on to a Pro Jr and was digging that.

I recall it was a pretty versatile little beast that could really sizzle. Have fun!

sizzle is a great word for it! i've been really drawn to the clean channel, it's a little more to my taste than the lead channel thus far. been having a lot of fun overdriving the clean circuit, sounds so great. i'm gonna build a new channel footswitch for it next week and then explore the lead channel a bit more
 




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